DiRT 3

Since It's jam session it can be boosted easily, just set up a race with a partner and exchange wins, you can combine this with "The Lively Set" if you want by just varying the event type and car selection so you work your way through all 5 cars. If doing normally just refer to "The Lively Set" again for the event/class you need to look for when searching so you will be able to use one of the cars. Win 5 races with any combination of the 5 cars and the trophy is yours.